Cyber threats are growing more prevalent and scary, from Russian hacking in the 2016 American presidential election to the massive theft of corporate intellectual property to the growing danger of cyber acts of mass disruption. Today, there are only two kinds of companies: those who have been hacked and those who just don’t know it yet. How can policymakers, business leaders, and the rest of us make sense of this evolving landscape? Who are the most serious cyber bad actors? Is deterrence ever possible in cyberspace? These are some the questions we explore, with a walk through we should know, what we do know, and what we don't know about digital dangers.